Magnesium chloride, a chemical used as a winter road de-icer, corrodes truck bodies, suspensions, electrical wiring and brakes. Yet its use on U.S. highways continues to grow.

The caustic impact of mag chloride on trucks was revealed by Heavy Duty Trucking in a 2001 article entitled Killer Chemicals. It was also the subject of a 2002 bulletin from the ATA’s Technology & Maintenance Council. “Magnesium chloride- and calcium chloride-based road ice clearing products used by certain states leads to an increased occurrence of corrosion on vehicles, causing significant damage in as quickly as a single winter season,” the bulletin reads.
It is still available on the TMC web site at www.tmc.truckline.com.
Yet despite the warnings sounded three years ago, mag chloride’s insidious impacts on trucks and trucking have been ignored by most state highway departments. Use of the chemical continues to increase.
Last week, the Colorado Department of Transportation announced it plans to use magnesium chloride among other products to keep roads clear of ice and snow this winter. Colorado is hardly alone.
The Texas DOT on its web site, notes that the department will treat critical areas with magnesium chloride. ”Several trucks are equipped to distribute the liquid spray for anti-icing before storms and de-icing to remove ice already on the road,” the site says.
The Indiana DOT web site boasts in an online brochure that in 2003, department used 161,643 gallons of magnesium chloride.
Idaho’s DOT web site offers an article by a department engineer who lauds mag chloride and calls its use on Idaho highways a “success.”
Success for many road departments is measured in dollars. There is no doubt that mag chloride is cheaper than other winter measures, as was demonstrated by a 1995 study in Washington State. Two highway sections of 20 lane-miles were compared. One was treated with sand, the other was pre-treated with magnesium chloride to prevent icing in the first place. The sand and its distribution cost $3,525; the cost to buy and distribute mag chloride was $383.
Like the Idaho engineer who called mag chloride a success, that study did not consider the cost of corrosion to vehicle owners or its possible negative impact on highway safety.
But those realities remain, and there are efforts to help fleets deal with it.
* At the SAE Commercial Vehicle Engineering Congress & Exhibition in Chicago later this month, a technical session will deal with the broad subject of corrosion. According to the SAE literature, “panelists will describe ongoing test programs and assessment activities concerning vehicle corrosion mechanisms and anti-icing chemicals.” The session will be chaired by Victor A. Suski, an expert of the problems of corrosive de-icing chemicals.
* And in February, the TMC’s Transportation Technology Exhibition in Tampa, Fla., will offer a technical session called "Corrosion Prevention Solutions: An Overview of Available Technologies." John Sullivan, vp for maintenance and purchasing for Performance Transportation Services will lead the session,
According to a TMC position paper issued in November 2002, the states that use mag chloride to one degree or another include Arkansas, District of Columbia, Idaho, Kentucky, Louisiana, Maryland, Michigan, Montana, Nebraska, New Mexico, New York, Oklahoma, Oregon, Pennsylvania, Texas, Utah, Vermont, Virginia, Washington, Wisconsin and Wyoming.